The present invention relates to an optical system for alternative or simultaneous direction of light originating from two scenes to an eye of a viewer, and more particularly, to an optical system which employs a planar opyics approach for alternative or simultaneous direction of light originating from two scenes to the eye of a viewer. The system according to the invention may thus be used to provide inventive bifocal eyeglasses, using which does not require inconvenient head and eye positioning relative to the viewed scene as associated with using conventional bifocal eyeglasess. The present invention further relates to an optical system for simultaneous direction of light originating from two scenes to an eye or both eyes of a viewer using geometric or planar optic approaches. The system according to the invention does not employ active radiation for display.
As used herein in the specification and claims, the term xe2x80x98scenexe2x80x99 refers to an object or set of objects as perceived by a viewer through passive radiation, i.e., through radiation which comes from outside the system of the present invention.
The passive radiation may for example be radiation reflected or scattered by the object or objects and it may also be radiation which is emitted from the object or objects. In other words, passive radiation is radiation which comes from outside the system of the present invention and which would have perceived by the viewer even without the system of the present invention.
By contrast, the term xe2x80x98active radiationxe2x80x99 as used herein is intended to include radiation which originates from a component of the system in question. Thus, for example, a conventional head-up-display (HUD) system includes a cathode ray tube (CRT), so that the radiation generated by the CRT is active radiation. A view of active radiation as herein defined is defined herein as a display.
The term xe2x80x98scenexe2x80x99 as referred herein specifically excludes any type of a display formed by active radiation, as used for example in HUD systems. The term xe2x80x98imagexe2x80x99 as used herein reads upon both scene and display, whereas a real image refers to a scene and a virtual image refers to a display.
Since the system of the present invention includes no source of radiation, all the radiation perceived by the viewer using the system of the present invention is passive radiation. It is to be noted that, as defined herein, in the context of the present invention, even radiation which is emitted, for example, from a television screen or computer monitor, is considered passive radiation since neither the television screen nor the computer monitor is a part of the system of the present invention.
A high percentage of the population is in need of eyeglasses due to various vision defects.
Conventional eyeglasses typically include a frame to support the glasses in a suitable position in front of the eyes of the viewer, and two lenses implemented within the frame, one for each of the eyes of the viewer. Each of the lenses is acquired a focal characteristic to compensate for its specific eye vision defect.
Thus for example, in cases of myopia, which is a vision defect of focus, resulting from too much power in the eye lens and cornea and/or too long an eyeball, the image of a distant object falls ahead of the retina and cannot be focused sharply due to extensive amount of positive focal power, a negative lens is chosen so that its image is formed at the most distant point on which the myopic eye can focus.
On the other hand, in cases of hyperopia, the reverse of myopia which results from too little power in the refracting elements of the eye and/or too short an eyeball, the image of a distant object is formed (when the eye is relaxed) behind the retina. Hyperopia is therefore compensated for by a positive lens.
Myopia and hyperopia are vision defects associated with viewing distant objects. Presibyopia, on the other hand, is an example for a vision defect associated with viewing close objects, which in many cases impairs the ability to read. Presibyopia results from the hardening of the material of the lens which typically comes with age, and leads to a limited ability to focus (accommodate) the eye with respect to close objects. Presibyopia is therefore compensated for by a positive lens which enables a user to comfortably read.
However, in many cases a single eye suffers from both a long distance vision defect such as myopia or hipermyopia limiting its landscape vision capabilities and a short distance vision defect such as presibyopia limiting its reading capabilities.
A person with such a dual eye defect is in need of either two sets of eyeglasses, the first offers corrective optics for the long distance vision defect and the other offers corrective optics for the short distance vision defect, or alternatively, a set of what is known in the art as bifocal eyeglasses which include bifocal lenses, each is in fact the combination of two lenses having given (yet different) focal lengths and optical characteristics, arranged one aside the other. Multifocal eyeglasses are also known although less frequently used due to their high price and the inability of many individuals to accommodate to their use.
Nevertheless, both these solutions suffer limitations. Using two pairs of eyeglasses, one pair for reading and the other for long distance viewing, requires changing the glasses each time a user moves his site from a close to a distant object, and wise versa. Using bi- or multifocal eyeglasses dictates different lines of site for viewing close and distant objects and limits the field of view in both cases. Typically, for reading the user is required to lower his eyes while maintaining a substantially straight forward head position. Should the close object be positioned straight ahead relative to the viewer, in order to sharply view the close object, the viewer is required to tilt his head backwards and at the same time to lower his eyes. All this leads in many cases to head and neck problems, which is the reason why many individuals prefer not to use bifocal eyeglasses.
There is thus a widely recognized need for, and it would be highly advantageous to have, an optical system for alternative or simultaneous direction of light originating from two scenes to the eye of a viewer, as such a system can be used to provide bi- or multi focal eyeglasses, using which does not require inconvenient head and eye positioning relative to the viewed scene.
Many situations exist in which a viewer is interested in viewing scenes located in different locations with respect to the viewer. Examples include but are not limited to (i) taking notes while viewing a blackboard, a lecturer or a display (e.g., a slides screen), in this case the viewer is interested at viewing both his notes, which are typically located on a table or a writing board, and the blackboard, lecturer or display; (ii) drawing while viewing the object to be drawn (e.g., landscape), in this case the viewer is interested at viewing both his drawing board and the drawn object; (iii) typing on a keyboard while viewing the screen, in this case a non professional typist is interested at viewing both the keyboard and the screen; (iv) locking at or reading from a printed matter (e.g., a map, a guide book, etc.) while viewing another scene (e.g., a road, an instrument, etc.), in this case the viewer is interested at viewing both the printed matter and the other scene.
However, since the field of view in which a viewer can focus is relatively narrow, in the above and similar situations the viewer is required to move his eyes site back and forth between the scenes, such that at any given time the viewer sees only one of the scenes. This in turn creates disadvantages since (i) when the viewer sees one scene he may not become aware to a change in the other scene, thus for example, a driver or a pilot, while viewing a road or navigation map, cannot at the same time view the road or sky ahead; and (ii) the viewer finds it difficult to compare between scenes, thus for the painter it is difficult to compare his drawing to the object being drawn, for the typist it is difficult to detect a typological error, for the student it is harder to accurately copy schemes from the blackboard or display into his notes, etc.
There is thus a widely recognized need for, and it would be highly advantageous to have, an optical system for simultaneous direction of light originating from two scenes to the eyes of a viewer.
According to the present invention there is provided an optical system for alternative or simultaneous direction of light originating from at least two scenes to the eye of a viewer. There is further provided an optical system for simultaneous direction of light originating from two scenes to an eye or both eyes of a viewer which can be used to enable the viewer to simultaneously view a first scene and a second scene. The optical system according to the present invention involves use of only passive radiation originating from the viewed scenes and in sharp contrast to head-up-display (HUD) systems does not employ active radiation.
According to further features in preferred embodiments of the invention described below, the system comprising (a) a first lens having a first focal length; (b) a second lens having a second focal length, the first and second lenses being positioned aside one another in front of one of the eyes of the viewer, such that a single light beam from any of the scenes passes only through one of the first and second lenses; and (c) an optical arrangement for directing incident light originating from the first scene and passing through the first lens into the eye of the viewer, and at the same time, for directing incident light originating from the second scene and passing through the second lens into the eye of the viewer, the optical arrangement being positioned between the first and second lenses and the eye of the viewer.
According to another embodiment of the invention the system comprising (a) a magnifying-collimating eyepiece lens having a short focal length, for magnifying a close scene and for collimating light passing through the magnifying-collimating lens; (b) an optical arrangement for directing incident light originating from the close scene and passing through the magnifying-collimating lens into the eye of the viewer, and at the same time, for directing incident light originating from a distant scene into the eye of the viewer; and (c) a corrective eyepiece lens for compensating for a long distance visual defect, the corrective lens being positioned between the optical arrangement and the eye of the viewer.
According to still further features in the described preferred embodiments the optical arrangement includes a holographic plate.
According to still further features in the described preferred embodiments the holographic plate includes at least one holographic optical element.
According to still further features in the described preferred embodiments the holographic plate includes a first input holographic optical element for permitting incident light passing through the first lens to enter the holographic plate.
According to still further features in the described preferred embodiments the holographic plate includes a first input holographic optical element for permitting incident light passing through the magnifying-collimating lens to enter the holographic plate.
According to still further features in the described preferred embodiments the holographic plate further includes a second input holographic optical element for permitting incident light passing through the second lens to enter the holographic plate.
According to still further features in the described preferred embodiments the holographic plate further includes a second input holographic optical element for permitting incident light originating from the distant scene to enter the holographic plate.
According to still further features in the described preferred embodiments the holographic plate further includes an output holographic optical element for permitting light entering the holographic plate to leave the holographic plate and reach the eye of the viewer.
According to still further features in the described preferred embodiments the optical arrangement includes at least one reflective optical element.
According to still further features in the described preferred embodiments the system further comprising (d) a light blocking mechanism for, at least at a given period of time, blocking light of one of the first and second scenes from arriving onto the eye of the viewer.
According to still further features in the described preferred embodiments the optical system further comprising (d) a light blocking mechanism for, at least at a given period of time, blocking light of one of the close and distant scenes from arriving onto the eye of the viewer.
According to another embodiment of the invention provided are eyeglasses comprising two optical systems as in any of the above described embodiments.
According to another embodiment of the invention provided is a headset for three-dimensional viewing comprising two optical systems including a light blocking mechanism.
According to another embodiment of the invention provided is an optical system to be used by a viewer to acquire a three-dimensional perception of a scene presented by a first image and a second image each of the first and second images contain parallax information of the scene, the system comprising a first holographic plate and a second holographic plate, each of the first and second holographic plates including (a) a body made of a light transmitting material, the body having a first side and a second side; (b) at least one input holographic optical element formed in the first side of the body, the material and each of the input holographic optical elements are selected such that incident light entering the body and having a given direction is diffracted and undergoes substantially total internal reflection; and (c) at least one output holographic optical element formed in the second side of the body, such that light arriving at any of the output holographic optical elements exits the body in a direction substantially similar to the given direction of the incident light; wherein, the first holographic plate is for permitting substantially only light originating from the first image to arrive at one eye of the viewer, whereas the second holographic plate is for permitting substantially only light originating from the second image to arrive at the other eye of the viewer.
According to still further features in the described preferred embodiments each of the holographic optical elements further includes a light blocking mechanism to effect the permissions.
According to further features in preferred embodiments of the invention described below, provided is a method for enabling a viewer to view a first scene and a second scene, the method comprising the steps of (a) providing the viewer with a first eyepiece lens having a first focal length; (b) providing the viewer with a second eyepiece lens having a second focal length, the first and second lenses being positioned aside one another in front of one of the eyes of the viewer, such that a single light beam from any of the scenes passes only through one of the first and second lenses; and (c) providing the viewer with an optical arrangement for directing incident light originating from the first scene and passing through the first lens into the eye of the viewer, and at the same time, for directing incident light originating from the second scene and passing through the second lens into the eye of the viewer, the optical arrangement being positioned between the first and second lenses and the eye of the viewer.
According to further features in preferred embodiments of the invention described below, provided is a method to be used by a viewer to view a close scene and a distant scene, the method comprising th steps of (a) providing the viewer with a magnifying-collimating eyepiece lens having a short focal length, for magnifying the close scene and for collimating light passing through the magnifying-collimating lens; (b) providing the viewer with an optical arrangement for directing incident light originating from the close scene and passing through the magnifying-collimating lens into an eye of the viewer, and at the same time, for directing incident light originating from the distant scene into the same eye of the viewer; and (c) providing the viewer with a corrective eyepiece lens for compensating for a long distance visual defect, the corrective lens being positioned between the optical arrangement and the same eye of the viewer.
According to further features in preferred embodiments of the invention described below, provided is an optical system for enabling a viewer to simultaneously view a first scene and a second scene, both the first and second scenes are perceived by the viewer through passive radiation, the system comprising (a) a head arrangement for mounting the system on the head of the viewer, for positioning the optical system in front of an eye of the viewer; and (b) a beamsplitter being positioned such that light originating from the first scene and light originating from the second scene both are simultaneously directed into the eye of the viewer.
According to still further features in the described preferred embodiments the first scene is a close scene and the second scene is a distant scene, such that light originating from the distant scene is naturally substantially collimated, the system further comprising (c) a collimating lens for collimating light originating from the close scene, the collimating lens being supported by the head arrangement.
According to still further features in the described preferred embodiments the first and second scenes are both close scenes, such that light originating from any of the scenes is a non-collimated light, the system further comprising (c) a first collimating lens for collimating light originating from the first scene, the first collimating lens being supported by the head arrangement; and (d) a second collimating lens for collimating light originating from the second scene, the second collimating lens being supported by the head arrangement.
According to still further features in the described preferred embodiments the system further comprising (c) at least one reflector being supported by the head arrangement, the at least one reflector being for directing light originating from the first scene onto the beamsplitter.
According to still further features in the described preferred embodiments the system further comprising (c) a corrective optical lens for correcting a vision defect of the viewer, the corrective optical lens being positioned between the beamsplitter and the eye of the viewer, the corrective optical lens being supported by the head arrangement.
According to further features in preferred embodiments of the invention described below, provided is a method for enabling a viewer to simultaneously view a first scene and a second scene, both the first and second scenes are perceived by the viewer through passive radiation, the method comprising the step of (a) providing the viewer with a beamsplitter positioned such that light originating from the first scene and light originating from the second scene both simultaneously directed at an eye of the viewer.
According to still further features in the described preferred embodiments the first scene is a close scene and the second scene is a distant scene, such that light originating from the distant scene is naturally substantially collimated, the method further comprising the step of (b) providing the viewer with a collimating lens for collimating light originating from the close scene.
According to still further features in the described preferred embodiments the first and second scenes are both close scenes, such that light originating from any of the scenes is a non-collimated light, the method further comprising the steps of (b) providing the viewer with a first collimating lens for collimating light originating from the first scene; and (c) providing the viewer with a second collimating lens for collimating light originating from the second scene.
According to still further features in the described preferred embodiments the method further comprising the step of (b) providing the viewer with at least one reflector, the at least one reflector being for directing light originating from the first scene onto the beamsplitter.
According to still further features in the described preferred embodiments the method further comprising the step of (b) providing the viewer with a corrective optical lens for correcting a vision defect of the viewer, the corrective optical lens being positioned between the beamsplitter and the eye of the viewer.
According to still further features in the described preferred embodiments the beamsplitter is moveable with respect to the head arrangement for permitting the viewer to adjust the system at viewing the first and second scenes when the viewer moves his head and for permitting the viewer to select another pair of scenes to be simultaneously viewed.
According to still further features in the described preferred embodiments the first and second scenes are both distant, such that light originating from the scenes is naturally substantially collimated.
According to still further features in the described preferred embodiments at least one of the at least one reflectors and the beamsplitter is moveable with respect to the head arrangement for permitting the viewer to adjust the system at viewing the first and second scenes when the viewer moves his head, and for permitting the viewer to select at least one replacement scene to be simultaneously viewed with the second scene.
According to still further features in the described preferred embodiments the beamsplitter and the reflector are formed as a first surface and a second surface, respectively, of a single optical element having a volume.
According to still further features in the described preferred embodiments the reflector is a collimating reflector and the beamsplitter is a collimating beamsplitter, such that light originating from the first scene is collimated by the collimating reflector before reaching the beamsplitter.
According to still further features in the described preferred embodiments the beamsplitter and the at least one reflector are arranged with respect to the first scene and with respect to the eye of the viewer such that the first scene is viewed in a steep angle.
According to still further features in the described preferred embodiments the beamsplitter is a collimating beamsplitter, such that light originating from the first scene is collimated by the collimating beamsplitter before reaching the eye of the viewer.
According to further features in preferred embodiments of the invention described below, provided is a headset for enabling a viewer to simultaneously view a first scene and a second scene comprising two optical systems as described above each of the two systems being positioned in front of one of the eyes of the viewer.
According to further features in preferred embodiments of the invention described below, provided is a headset for enabling a viewer to simultaneously view a first scene with one eye and a second scene with the other eye, the headset comprising an optical systems as described above, the optical system being positioned in front of the one eye of the viewer, the beamsplitter functions substantially only as a reflective surface, so that light originating from the first scene is directed onto the one eye of the viewer while the one eye of the viewer is directed towards the second scene, whereas at the same time, the second eye of the viewer is directed at the second scene.
According to further features in preferred embodiments of the invention described below, provided is an optical system for enabling a viewer to simultaneously view a first scene and a second scene, both the first and second scenes are perceived by the viewer through passive radiation, the system comprising a holographic plate, the holographic plate including (a) a body made of a light transmitting material, the body having a first side and a second side; (b) at least one input holographic optical element formed in the first side of the body, the material and each of the at least one input holographic optical elements are selected such that incident light entering the body and having a given direction is diffracted and undergoes a substantially total internal reflection; and (c) at least one output holographic optical element formed in the second side of the body, such that light arriving at any of the at least one output holographic optical elements exits the body in a direction substantially similar to the given direction of the incident light (i.e., enters from one side of the plate, exits from the other) and reaches an eye of the viewer; wherein, the holographic plate is positioned with respect to the eye of the viewer, and the at least one input and output holographic optical elements are positioned with respect to the body, such that light originating from both the first and second scenes is simultaneously directed into the eye of the viewer.
According to still further features in the described preferred embodiments the body is curved at least at one location.
According to still further features in the described preferred embodiments the first scene is a close scene and the second scene is a distant scene, such that light originating from the distant scene is naturally substantially collimated, the system further comprising (d) a collimating lens for collimating light originating from the close scene.
According to still further features in the described preferred embodiments the first and second scenes are both distant, such that light originating from both scenes is naturally substantially collimated.
According to still further features in the described preferred embodiments the first and second scenes are both close scenes, such that light originating from any of the scenes is a non-collimated light, the system further comprising (d) a first collimating lens for collimating light originating from the first scene, the first collimating lens being positioned between the first scene and the holographic plate; and (e) a second collimating lens for collimating light originating from the second scene, the second collimating lens being positioned between the second scene and the holographic plate.
According to still further features in the described preferred embodiments the system further comprising (d) a collimating lens being positioned between the holographic plate and the eye of the viewer, for collimating light originating from both the first and second scenes.
According to still further features in the described preferred embodiments the system further comprising (d) a corrective optical lens for correcting a vision defect of the viewer, the corrective optical lens being positioned between the holographic plate and the eye of the viewer.
According to further features in preferred embodiments of the invention described below, provided is a headset for enabling a viewer to simultaneously view a first scene and a second scene comprising two optical systems as described above, each of the two systems being positioned in front of one of the eyes of the viewer.
According to further features in preferred embodiments of the invention described below, provided is a headset for enabling a viewer to simultaneously view a first scene with one eye and a second scene with the other eye, the headset comprising an optical systems as described, the optical system being positioned in front of the one eye of the viewer, the system permitting light from the first scene to arrive to the one eye of the viewer, while at the same time blocking light originating from the second scene from arriving at the one eye while the one eye of the viewer is directed towards the second scene, whereas, at the same time, the second eye of the viewer is directed at the second scene.
According to still further features in the described preferred embodiments the first and second scenes form a pair of related scenes, the pair of related scenes is selected from the group of pairs of scenes consisting of a notexe2x80x94a blackboard, a notexe2x80x94a lecturer, a notexe2x80x94a screen, a drawxe2x80x94a drawn object, a keyboardxe2x80x94a screen, a printed matterxe2x80x94screen, a printed matterxe2x80x94a road ahead and a printed matterxe2x80x94sky ahead.
According to still further features in the described preferred embodiments provided is a method for enabling a viewer to simultaneously view a first scene and a second scene, both the first and second scenes are perceived by the viewer through passive radiation, the method comprising the steps of (a) providing the viewer with a holographic plate through which the viewer sees the scenes, the holographic plate including (i) a body made of a light transmitting material, the body having a first side and a second side; (ii) at least one input holographic optical element formed in the first side of the body, the material and each of the at least one input holographic optical elements are selected such that incident light entering the body via at least one input holographic optical element and having a given direction undergoes a substantially total internal reflection; and (iii) at least one output holographic optical element formed in the second side of the body, such that light arriving at any of the at least one output holographic optical elements exits the body in a direction substantially similar to the given direction of the incident light and reaches one of the eyes of the viewer; and (b) positioning the holographic plate with respect to the eye of the viewer, and the at least one input and output holographic optical elements with respect to the body, such that passive light radiation originating from both the first and second scenes is simultaneously directed into the eye of the viewer.
The present invention successfully addresses the shortcomings of the presently known configurations by providing an optical system for alternative or simultaneous direction of light from two scenes to the eye of a viewer, as such an optical system (i) may replace bifocal eyeglasses and be used with more ease and comfort as it requires no change in head positioning, nor a change in the direction at which the eyes of the viewer are directed at, as bifocal eyeglasses require upon changing from long distance to short distance viewing; (ii) may be used for three-dimensional viewing and for (iii) bringing visual information typically outside the field of view of the viewer into that field of view, without the viewer required to change his head positioning and/or eyes direction. The present invention further addresses the shortcomings of the presently known configurations by providing an optical system for simultaneous direction of passive light radiation originating from two scenes to the eye of a viewer which can be used to enable the viewer to simultaneously view pairs of related scenes.
Additional features, objectives and advantages of the optical systems according to the present invention are described in the following sections.